There has long been an opinion that if you drill the side electrode of a spark plug with a thin drill, the spark will increase. This method revives old worn-out spark plugs and actually makes them spark better. Why does this work, and is it worth doing it?
The process of refining spark plugs and their actual testing
To improve, you need to adjust the gap on the spark plugs, and drill its side electrode in the center with a 1 mm drill. After this it will start working better.
To check the effectiveness of the modernization, a special device is used that simulates the conditions in the engine cylinder, namely creating high pressure.
In atmospheric conditions, spark plugs almost always work well, but at high pressure they begin to blow. Before modification, the tested spark plug worked without failures in conditions up to 16 atm. Immediately after drilling, it easily overcomes this threshold and can withstand much more.
All this is explained by the formation of metal burrs on the back side of the electrode after drilling. Once they are removed, the spark plug again stops working correctly when the pressure rises to 16 atm.
Thus, the improvement from refining the spark plugs is observed for a short time until the burrs burn out. In fact, the theory about increasing engine power after drilling the side electrode turns out to be untenable. Trimming it doesn't work either.
It is best to simply change the spark plugs according to the replacement schedule.
